390 research outputs found

    Theorising VET without ‘VET theory’? Foundations and fragmentation of Anglophone VET research

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    Whilst VET in German-speaking countries and its research base are well-known internationally, its theoretical foundations are not shared in countries where VET emerged later and has undergone more circuitous forms of theorisation. The significance of these different international understandings of the field is explored here through a comparative discussion of the theorisation of VET in English-speaking countries. A critical review of key contributions to this theorisation shows it to draw on a wide range of external disciplines, in a problematic relationship with both a contested liberal education tradition and with neoliberal policy; and within a fragmented field of knowledge production, where it competes with alternative claims to expertise that limit its contribution to the field of policy and practice. It is concluded that, whilst this problematising and problematic theorisation of VET in the Anglosphere has produced significant contributions, their effect on policy and practice has been delayed or distorted, and that significant investment in autonomous research capacity will be necessary for any meaningful renewal of VET

    Optimization of crystal nucleation close to a metastable fluid-fluid phase transition

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    The presence of a metastable fluid-fluid critical point is thought to dramatically influence the crystallization pathway, increasing the nucleation rate by many orders of magnitude over the predictions of classical nucleation theory. We use molecular dynamics simulations to study the kinetics of crystallization in the vicinity of this metastable critical point and throughout the metastable fluid-fluid phase diagram. To quantitatively understand how the fluid-fluid phase separation affects the crystal nucleation, we evaluate accurately the kinetics and reconstruct the thermodynamic free-energy landscape of crystal formation. Contrary to expectations, we find no special advantage of the proximity of the metastable critical point on the crystallization rates. However, we find that the ultrafast formation of a dense liquid phase causes the crystallization to accelerate both near the metastable critical point and almost everywhere below the fluid-fluid spinodal line. These results unveil three different scenarios for crystallization that could guide the optimization of the process in experimentsThis work has been supported by the MINECO of the Spanish government through Grants No. FIS2012-31025 and FIS2011-22603. LX thanks the financial support from MOST 973 of China (Grants No. 2015CB856800 and 2012CB921404) and National Science Foundation of China (Grants No. 11174006 and 11290162). HES thanks the NSF Chemistry Division for support (grants CHE 0911389, CHE 0908218, and CHE 1213217). SVB thanks the Office of the Academic Affairs of Yeshiva University for funding the Yeshiva University high-performance computer cluster and acknowledges the partial support of this research through Dr. Bernard W. Gamson computational Science Center at Yeshiva College. (FIS2012-31025 - MINECO of the Spanish government; FIS2011-22603 - MINECO of the Spanish government; 2015CB856800 - MOST 973 of China; 2012CB921404 - MOST 973 of China; 11174006 - National Science Foundation of China; 11290162 - National Science Foundation of China; CHE 0911389 - NSF Chemistry Division; CHE 0908218 - NSF Chemistry Division; CHE 1213217 - NSF Chemistry Division; Office of the Academic Affairs of Yeshiva University; Dr. Bernard W. Gamson computational Science Center at Yeshiva College)Published versio

    Retrieving and recontextualising VET theory

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    To what extent can we speak of theory specific to vocational education and training (VET) and what is its relevance today? This Special Issue 19 of bwp@ aims to (re)ignite academic discourse on VET theory, retrieving earlier theorisation specific to this field, mainly from Germany, Austria, and Switzerland (the DACH countries) and connecting it both with international perspectives and contemporary debates. We invite papers in English or German that engage with these debates. From an international perspective, the DACH countries are extraordinary both in their proposition of theories of VET sui generis and especially in their influence on the field of policy and practice. By contrast, for example in English-speaking countries, influential theories that address the question of vocational study, whilst drawing extensively on philosophical and social science concepts, developed largely in opposition to policy and practices that positioned vocational learning as an inferior pathway and narrowed its educational scope. The dual apprenticeship model has been widely imitated internationally but without regard to the social partnerships, labour markets and education workforce developed in Germany, and the theories that shaped this system are neither translated nor widely discussed in other languages. While there are several approaches to VET theory, the core of all these approaches is a framework of normative goals of education, a characterisation of how these goals can be reached through vocational education in particular and the formulation of (education) policy implications that are necessary for successful implementation. For example, Kerschensteiner (1901, 1966/1904) in his emphasis on civic virtues as a central aim of education, drew attention to the possibility of attaining such virtues through work, but acknowledged the necessity of a foundation in general education. In contrast, post-war critical approaches, which regularly draw on critical theory (see Habermas 1968; Horkheimer & Adorno 1947), and can be dated to the 1960s and 1970s, identify autonomy and emancipation as central objectives of education (e.g. Lempert 1971; Blankertz 1974, 1979, 1982). The main challenge of VET theory was to explain how these goals also can be reached through vocational education. Blankertz’s answer lay in emphasizing the role of the VET school in widening and deepening knowledge associated with the workspace. The value of these approaches for contemporary VET is dependent on their adaptation to contemporary problems that VET and society are experiencing: migration and integration; climate change and resource consumption, digitisation and globalisation. The tertiarisation of both the economy and of education, as the service sector employs a greater proportion of the population and a growing number of young people enter higher education, even in Germany, also calls into question the relevance of established VET theories. As the structures and forms of organisation that have sustained VET since the 1970s have given way to new social formations and new forms of precarity, the relevance of theories developed during the long period of post-war growth is called into question. Correspondingly, whether a critical standpoint can still be clearly located after the “fall of metaphysics” (Adorno 1998/1965) has also been deemed as questionable (cf. Schäfer 2005). Furthermore, a succession of de-centring approaches including post-structuralist, postmodernist and post-anthropocentric paradigms has suggested the erosion of earlier ‘grand narratives’, the supersession of the ‘enlightenment project’ and even questioned the progressive potential of human labour that explicitly VET theories tend to take for granted. Call for Papers bwp@ Spezial 19 2 Against this background, the bwp@ Special invites contributions that address both VET theory and its application to contemporary issues. The aim is to stimulate a discussion on the continuing significance of VET theory. The aim is to provide space for ideas on how the discipline and its subject could position itself, both nationally and beyond national borders, in its normative-theoretical contours and/or in relation to VET policy and VET practice

    Consumption of carotenoids not increased by bacterial infection in brown trout embryos (Salmo trutta).

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    Carotenoids are organic pigment molecules that play important roles in signalling, control of oxidative stress, and immunity. Fish allocate carotenoids to their eggs, which gives them the typical yellow to red colouration and supports their resistance against microbial infections. However, it is still unclear whether carotenoids act mainly as a shield against infection or are used up during the embryos' immune defence. We investigated this question with experimental families produced from wild-caught brown trout (Salmo trutta). Singly raised embryos were either exposed to the bacterial pathogen Pseudomonas fluorescens or sham-treated at one of two stages during their development. A previous study on these experimental families reported positive effects of egg carotenoids on embryo growth and resistance against the infection. Here, we quantified carotenoid consumption, i.e. the active metabolization of carotenoids into compounds that are not other carotenoid types, in these infected and sham-infected maternal sib groups. We found that carotenoid contents mostly decreased during embryogenesis. However, these decreases were neither linked to the virulence induced by the pathogen nor dependent on the time point of infection. We conclude that egg carotenoids are not significantly used up by the embryos' immune defence

    Maternal allocation of carotenoids increases tolerance to bacterial infection in brown trout.

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    Life-history theory predicts that iteroparous females allocate their resources differently among different breeding seasons depending on their residual reproductive value. In iteroparous salmonids there is typically much variation in egg size, egg number, and in the compounds that females allocate to their clutch. These compounds include various carotenoids whose functions are not sufficiently understood yet. We sampled 37 female and 35 male brown trout from natural streams, collected their gametes for in vitro fertilizations, experimentally produced 185 families in 7 full-factorial breeding blocks, raised the developing embryos singly (n = 2960), and either sham-treated or infected them with Pseudomonas fluorescens. We used female redness (as a measure of carotenoids stored in the skin) and their allocation of carotenoids to clutches to infer maternal strategies. Astaxanthin contents largely determined egg colour. Neither egg weight nor female size was correlated with the content of this carotenoid. However, astaxanthin content was positively correlated with larval growth and with tolerance against P. fluorescens. There was a negative correlation between female skin redness and the carotenoid content of their eggs. Although higher astaxanthin contents in the eggs were associated with an improvement of early fitness-related traits, some females appeared not to maximally support their current offspring as revealed by the negative correlation between female red skin colouration and egg carotenoid content. This correlation was not explained by female size and supports the prediction of a maternal trade-off between current and future reproduction

    Optimization of crystal nucleation close to a metastable fluid-fluid phase transition

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    The presence of a metastable fluid-fluid critical point is thought to dramatically influence the crystallization pathway, increasing the nucleation rate by many orders of magnitude over the predictions of classical nucleation theory. We use molecular dynamics simulations to study the kinetics of crystallization in the vicinity of this metastable critical point and throughout the metastable fluid-fluid phase diagram. To quantitatively understand how the fluid-fluid phase separation affects the crystal nucleation, we evaluate accurately the kinetics and reconstruct the thermodynamic free-energy landscape of crystal formation. Contrary to expectations, we find no special advantage of the proximity of the metastable critical point on the crystallization rates. However, we find that the ultrafast formation of a dense liquid phase causes the crystallization to accelerate both near the metastable critical point and almost everywhere below the fluid-fluid spinodal line. These results unveil three different scenarios for crystallization that could guide the optimization of the process in experiments

    IUCF High Intensity Polarized Ion Source

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    This research was sponsored by the National Science Foundation Grant NSF PHY-931478

    Trajectory studies of Polar Statospheric Cloud Lidar Observations at Sodankyla (Finland) during SESAME: comparison with box model results of particle evolution

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    Polar statospheric clouds (PSC) were observed with the milti-wavelengh lidar of the MOANA project during SESAME. The physical state, liquid or solid, of the cloud particles can be inferred from the lidar data. Using isentropic back-trajectories to obtain the thermal history of the sampled air masses, it is possible to reconcile most of the observations with current ideas on PSC formation and evolution. When the cloud particles were identified as liquid, changes in the size distributionof the droplets along the trajectory ewre calculated using micro-physical box model. Backscatter ratios ......Published165-1811.8. Osservazioni di geofisica ambientaleJCR Journalreserve

    What are the evolutionary constraints on larval growth in a trophically transmitted parasite?

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    For organisms with a complex life cycle, a large larval size is generally beneficial, but it may come at the expense of prolonged development. Individuals that grow fast may avoid this tradeoff and switch habitats at both a larger size and younger age. A fast growth rate itself can be costly, however, as it requires greater resource intake. For parasites, fast larval growth is assumed to increase the likelihood of host death before transmission to the next host occurs. Using the tapeworm Schistocephalus solidus in its copepod first intermediate host, I investigated potential constraints in the parasite’s larval life history. Fast-growing parasites developed infectivity earlier, indicating there is no functional tradeoff between size and developmental time. There was significant growth variation among full-sib worm families, but fast-growing sibships were not characterized by lower host survival or more predation-risky host behavior. Parental investment also had little effect on larval growth rates. The commonly assumed constraints on larval growth and development were not observed in this system, so it remains unclear what prevents worms from exploiting their intermediate hosts more aggressively

    Evidence for Liquid Droplets in a -65° Cold Cirrus Observed by LIDAR above Sodankyla (Finland) during SESAME

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    It is widely accepted that pure water cannot exist as liquid below about -40°C. Theoretical and laboratory studies confirm this behavior for pure water . Nevertheless, liquid droplets have been seldom observed in cirrus clouds down to -50°C. Miltiwaveleght depolarization LIDAR tecnique can help ti hunt usually cold supercooled clouds. The presence of non-depolarizing cloud layers is indicative of scattering with ylindrical symmetry, possible both with spherical droplets and with ice plates horizontally oriented. In this work, a -65°C cold, non- depolarizing cloud observed in Finland is analysed, concluding thath supercooled droplets are responsible for the absence of depolarization in most of the layer.PublishedSchliersee, Germany1.8. Osservazioni di geofisica ambientaleope
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